Let's keep the discussion here on the newsgroup so that all may benefit.
If Windows normally treats the external digitizer tablet as a mouse, then
OneNote can also use it. *However*, anything that is written in OneNote
using an external digitizer will be treated as a drawing and not as
handwriting. You will not be able to convert to text, nor search/index
this data.
There is no native support in OneNote for handwriting recognition - OneNote
relies on the Ink API provided by the Tablet PC OS. A frequent request
here is to support external digitizers in a future version of either
OneNote or of the Tablet PC OS. Most external digitizers do not have a
high enough sample rate to provide enough data for the Ink engine.